/*
 * (C) APUE
 * Implementation signal using sigaction
 * this signal call will not reset the signal handler to SIG_DFL
 */
#include "apue.h"

/* Reliable version of signal(), using POSXI sigaction(). */
Sigfunc *signal (int signo, Sigfunc *func)
{
	struct sigaction  act, oact;

	act.sa_handler = func;
	sigemptyset(&act.sa_mask);
	act.sa_flags = 0;
	if (signo == SIGALRM)
	{
#ifdef	SA_INTERRUPT
		act.sa_flags |= SA_INTERRUPT;
#endif
	}
	else
	{
#ifdef	SA_RESTART
		act.sa_flags |= SA_RESTART;
#endif
	}

	if (sigaction(signo, &act, &oact) < 0)
		return (SIG_ERR);

	return (oact.sa_handler);
}
